Surface Modification of Core-Shell Silver-Titania Nanocomposites with Copper Bipyridine–Phosphonates and Studies on Ag@TiO₂ Mediated Degradation of Organophosphates
Talebzadeh Farooji, Somayeh
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Silver nanoparticles, coated with a titania shell were prepared and were shown to be catalytically active for the rapid degradation of organothiophosphate methyl parathion (MeP). Formation of the degradation product, p-nitrophenolate (PNP) was monitored as a function of pH, using UV-Vis spectroscopy, and 31P NMR spectroscopy confirmed the hydrolysis is the predominant pathway for substrate breakdown under non-photocatalytic degradation. We have demonstrated that the unique combination of TiO2 and silver nanoparticles is required for catalytic hydrolysis with good reproducibility. This work represents the first example of MeP degradation using TiO2 doped with AgNP under mild and ambient conditions. It is suggested that higher surface acidity on the surface of Ag@TiO2 initiates the interaction with MeP. The analysis of the catalytic data and a proposed mechanism for organophosphates using Ag@TiO2 will be presented. We also report our efforts to functionalize Ag@TiO2 core-shell nanoparticles with copper bipyridine via organophosphate capping agent. Stabilized core-shell nanoparticles were further interacted with copper ions to give catalytically active species for organophosphates (OPs) degradation. We suggest that Ag@TiO2 may be integrated onto supporting materials for plasmon assisted catalytic transformations.